returns unmodifiable sets (#1071)

* returns an unmodifiable set when retrieving the available animation names and available animation clips instead of an unmodifiable collection. fixes: #1070

* remove unnecessary set wrapper.

jme3-core/src/main/java/com/jme3/anim/AnimComposer.java

@@ -3,7 +3,10 @@ package com.jme3.anim;
 import com.jme3.anim.tween.Tween;
 import com.jme3.anim.tween.Tweens;
 import com.jme3.anim.tween.action.*;
-import com.jme3.export.*;
+import com.jme3.export.InputCapsule;
+import com.jme3.export.JmeExporter;
+import com.jme3.export.JmeImporter;
+import com.jme3.export.OutputCapsule;
 import com.jme3.renderer.RenderManager;
 import com.jme3.renderer.ViewPort;
 import com.jme3.scene.control.AbstractControl;
@@ -206,12 +209,25 @@ public class AnimComposer extends AbstractControl {
         }
     }
 
-    public Collection<AnimClip> getAnimClips() {
-        return Collections.unmodifiableCollection(animClipMap.values());
+    /**
+     * Returns an unmodifiable set of all available animations. When an attempt
+     * is made to modify the set, an UnsupportedOperationException is thrown.
+     *
+     * @return the unmodifiable set of animations
+     */
+    public Set<AnimClip> getAnimClips() {
+        return Collections.unmodifiableSet(new HashSet<>(animClipMap.values()));
     }
 
-    public Collection<String> getAnimClipsNames() {
-        return Collections.unmodifiableCollection(animClipMap.keySet());
+    /**
+     * Returns an unmodifiable set of all available animation names. When an
+     * attempt is made to modify the set, an UnsupportedOperationException is
+     * thrown.
+     *
+     * @return the unmodifiable set of animation names.
+     */
+    public Set<String> getAnimClipsNames() {
+        return Collections.unmodifiableSet(animClipMap.keySet());
     }
 
     @Override

jme3-core/src/test/java/com/jme3/anim/AnimComposerTest.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2009-2019 jMonkeyEngine
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
+ *   may be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.jme3.anim;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * @author Remy Van Doosselaer
+ */
+public class AnimComposerTest {
+
+    @Test
+    public void testGetAnimClips() {
+        AnimComposer composer = new AnimComposer();
+
+        Assert.assertNotNull(composer.getAnimClips());
+        Assert.assertEquals(0, composer.getAnimClips().size());
+    }
+
+    @Test
+    public void testGetAnimClipsNames() {
+        AnimComposer composer = new AnimComposer();
+
+        Assert.assertNotNull(composer.getAnimClipsNames());
+        Assert.assertEquals(0, composer.getAnimClipsNames().size());
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public void testGetAnimClipsIsNotModifiable() {
+        AnimComposer composer = new AnimComposer();
+
+        composer.getAnimClips().add(new AnimClip("test"));
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public void testGetAnimClipsNamesIsNotModifiable() {
+        AnimComposer composer = new AnimComposer();
+
+        composer.getAnimClipsNames().add("test");
+    }
+
+}